Problem: Solve for $s$. $8-4s=s+13$ $s=$
We need to manipulate the equation to get $s $ by itself. $\begin{aligned} 8-4s&=s+13 \\\\ 8-4s {-s} &= s+13{-s} &&\gray{\text{Subtract s from each side.}}\\\\ -5s+8&=13 &&\gray{\text{Combine like terms.}}\\\\ -5s+8{-8} &= 13{-8} &&\gray{\text{Subtract 8 from each side.}}\\\\ -5s &=5 &&\gray{\text{Combine like terms.}}\\\\ \dfrac{-5s}{{-5}} &= \dfrac{5}{{-5}} &&\gray{\text{Divide each side by -5.}}\\\\ s &= {-1} &&\gray{\text{Simplify.}} \end{aligned}$ The answer: $s = { -1 }~~~~~~~~$ [Let's check our work!]